1. Technical Field
The present invention relates to a control unit for a vehicle and a control method for a vehicle.
2. Related Art
For example, Japanese Unexamined Patent Application Publication (JP-A) No. 2007-325372 has disclosed that an electric vehicle is controlled which includes a first motor that drives a primary driving wheel, a second motor that drives a secondary driving wheel, and a battery, the state of charge (SOC) and temperature of the electric battery are checked to determine whether it is possible to perform driving force distribution control, and the required torque of the second motor is decreased in the low SOC, and then the required torque of the first motor is decreased.
Turning driving force control to be performed by the motors, which uses the difference between left and right driving forces, is performed with the power of a high-voltage battery. The state of charge (SOC) of the high-voltage battery, however, makes a difference in the performance of the driving force control. Especially if the state of charge of the high-voltage battery lowers during a turn, it is impossible to perform turn assist control by performing the driving force control. Accordingly, a driver has to turn the steering wheel more or perform a deceleration operation. In such a case, the driver is required to respond in a shorter time in proportion to the vehicle velocity, and thus the driver would be requested to perform a complicated steering operation at medium to high vehicle velocity.
The technology described in JP-A No. 2007-325372 controls front and rear wheel torque distribution by using the output torques of the first motor and the second motor, but does not consider the turning driving force control, which uses the difference between left and right driving forces. Nothing is thus taken into consideration about compensating for the turn assist control by performing the driving force control if the state of charge of the high-voltage battery lowers during a turn. It is difficult in this case to compensate for the turn assist control by performing the driving force control.